Flexographic ink fountains



TAINs May 19, 195.9

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United States Patent O 2,887,050 FLEXOGRAPHIC INK FOUNTAINS Henry W. Moser, Haddonield, NJ., and William Grobman, Philadelphia, Pa., assignors to Samuel M. Langston Co., Camden, NJ., a corporation of New Jersey ographic and like ink fountains, of the type comprising a pair of contacting fountain rolls which Iform between them the bottom and opposite side walls of the ink reservoir, together with means coactive with the rolls for forming the end walls of the reservoir.

In its function of sealing olf the end of the reservoir, such end wall means has presented a serious problem, and a principal object of the present invention is to provide an end wall device having a relatively high sealing eiiciency.

Another object of the invention is to provide an end Wall device of the stated character the sealing eficiency of which will be unaffected by differential axial expansions and contractions of the fountain rolls.

Still another object is to provide an end wall device designed to utilize iluid pressure as a sealing medium.

The invention contemplates also the provision of an end wall device having self-conforming properties with respect to the convergent contours of the roll surfaces.

In the attached drawings:

Fig. l is a fragmentary diagrammatic end elevational view partly in section showing an end wall device for the reservoir of a ilexographic fountain made in accordance with our invention;

Fig. 2 is a sectional view on the line 2 2, Fig. 1;

Fig. 3 is a fragmentary diagrammatic end elevational view showing a modified form of end Wall device within the scope of the invention, and

Fig. 4 is a sectional view on the line 4 4, Fig. 3.

With reference to Figs. 1 and 2 of the drawings, the fountain rolls are indicated at 1 and 2 respectively. Conventionally the roll 1 has a steel face and the roll 2 has a face of flexible rubber or like resilient material. The rolls are in surface contact at 3, and the upwardly divergent surfaces 4 and 5 of the rolls form the sides of the ink reservoir, the normal level of the ink in the reservoir being indicated in broken line. The end of the reservoir are formed by identical members 6 of which one only is shown.

The member 6 consists of a generally V-shaped block which may suitably be made of metal. The convergent faces 7,7 of the block are contoured in conformity with the cylindrical surfaces 4 and 5 of the rolls and t accurately into the space therebetween, contacting the said surfaces continuously from the point 3 to points 8 and 9 above the ink level. In the present instance the block is held in place by two screws 11 and 12 threaded into the top of the block and extending freely through holes in arms 13 and 14 projecting from the frame 15. Nuts 34 and 35 on each of the screws at top and bottom of the arms respectively and adjustable into engagement with the proximate surfaces of the arms provide means for securing the block in adjusted position with respect to the roll surfaces. It will be evident that sealing contact between a reservoir and member of this character and the fountain rolls, being confined to the cylindrical surfaces of the rolls and being thereby divorced from the roll end faces, are not affected by unequal axial expansion and contraction of the rolls.

In accordance with the invention, the convergent faces 7,7 of the member 6 are provided with channels 16 and 17 which in the present instance occupy a common plane normal to the roll axes. These channels extend continuously from the apex of the V at point 3, where they intersect, to points above the ink level, these points, 18 and 19, respectively, being in proximity in the present instance to the ends of the block. Over their entire lengths, the channels confront the surfaces of the rolls and are in effect sealed by the latter.

A passage 21 extends downwardly from the top of the block 6 to the juncture of the channels: 16 and 17 and a tting 22 is threaded into the upper end of the said passage and with the latter provides a means for connecting the channels, by way of a llexible tube 23, to a source of fluid pressure (not shown) preferably air, Pressure applied to the said channels in this manner and tending to escape between the faces 7 of the block and the surfaces 4 and 5 of the rolls forms an effective barrier to ow of ink from the reservoir under the end wall. The effect is enhanced by provision of additional sets of channels 24, 25 and 26 corresponding to and paralleling the channels 16 and 17 and interposed between the latter set of channels and the side edges of the block, these channels having no direct connection with the pressure source.

In another embodiment of the invention, illustrated in Figs. 3 and 4, I employ a dam or end wall member 27 composed of a plastic material having in some degree the property of self-conformity to the surfaces of the rolls. Materials suitable for the purpose are soap and solid greases and also nylon and other available synthetic plastics. The darn members composed of' these materials, shaped to the roller in the same manner as the members 6 described above, conform closely to the surfaces of the roll and form sealed end walls for the :reservoir impermeable to the ink. In operation they tend to wear into an absolute conformity with the roll surfaces to effect an absolute seal.

Referring to Figs. 3 and 4, the plastic block 27 is shown confined at the top by a cap 28 which comprises a spring 29 conlned under compression between the inner top surface of the cap and a bearing plate 31 seated on the block. The cap itself is rigidly attached to the frame 32 of the machine through the medium of an arm 33 at the top` of the cap.

We claim:

l. In an ink fountain of the type described comprising a pair of contacting fountain rolls forming between them the bottom and opposite side walls of an ink reservoir, a generally V-shaped dam` member having its converging faces conforming to and contacting the peripheral surfaces of the rolls and forming an end wall for said reservoir, said member having a channel in each of said faces extending circumferentially of and sealed by the roll surface, together with means for connecting said channels to a fluid pressure source.

2. An ink fountain according to claim l wherein the channels meet at the apex of the V-shaped member.

3. An ink fountain according to claim 2 wherein the channels extend to points on the roll surfaces above the ink level in the reservoir.

4. An ink fountain according to claim. 3 including a plurality of sets of said channels forming an axially arranged series, one only of said sets having the means for connection to the fluid pressure source.

References Cited in the le of this patent UNITED STATES PATENTS 

